You may be surprised to discover that everything you know and touch in the natural world emits energy waves that are mostly invisible to the naked eye — including your own body.
These waves are called electromagnetic fields or EMFs and have existed right from the dawn of time when the natural rays of the sun hit the earth. The earth itself has its own magnetic field.
With the generation of electricity over a hundred years ago, mankind reached technological milestones such as the invention of the light bulb, the telegraph, transmitters, and radio communication — and as EMFs occur anywhere you have electric power, this meant a lot of artificial, human-created EMF entered our planet.
Fast-forward to today and we are now completely immersed and dependent on the technological devices that we use every day, from our Smartphones, computers, and microwaves, to the Wi-Fi router in our home, and the appliances we use every day, such as televisions and hairdryers.
Many experts now believe that constant EMF exposure may cause health risks.
In this post, we'll answer the question, "What is EMF?," discuss the sources and types of EMF, learn about the electromagnetic spectrum, and touch upon the controversy surrounding EMF radiation today:
Table of Contents
- What is EMF?
- Understanding Electric and Magnetic Fields
- Sources of EMF
- Types of EMF
The Electromagnetic Spectrum
- Radio Frequencies (RF)
- Infrared Radiation (IR)
- Visible Light
- Ultraviolet Radiation
- Gamma Rays
- Are EMFs Harmful?
- Key Takeaways
What is EMF?
The full-form of EMF is Electromagnetic Field — a field that is comprised of both an 'electric' and a 'magnetic' field. These fields travel perpendicular to each other in waves that are invisible to the human eye.
Based on Maxwell's equations, in the electromagnetic wave diagram below the electric field is shown as "E" and the magnetic field is shown as "B." As you can see the electric (E) and magnetic (B) waves are traveling perpendicular to each other.
A good example of natural EMF is the sun. The sun emits waves that generate both electric and magnetic fields, also known as 'radiation.' As the sun emanates EMFs, we can actually see the energy radiated as 'light.'
The EMF the sun generates is much lower in intensity than the high-intensity EMF waves that technology produces. So, if you live in an area surrounded by power lines for example, although you cannot see them, you are exposed to artificial EMFs.
Understanding Electric and Magnetic Fields
To gain a better understanding, let's take a closer look at the two different fields that make up EMF - electric and magnetic fields.
Both, electric and magnetic fields are energy (or radiation) generated by electricity which is simply the flow of electrons (or current) through a wire.
An electric field is created by what is known as 'voltage', the push or pressure that causes electrons or charges to move in the wire. Also known as electromotive force, as the voltage increases, so does the intensity of the electric field.
A magnetic field is what is created when a 'current' or electrons start to move through a wire or any electrical gadget. As the current or flow increases so does the intensity of the magnetic field. However, the further the magnetic field gets from its source the less intense it gets.
Electric fields are always present, even when a device is turned off. Magnetic fields, on the other hand, are only created when a current is moving and flowing, and this usually requires the device to be switched on as seen below:
So for example, since current is always flowing through power lines they are constantly generating a magnetic field. Magnetic fields can also transfer through walls, buildings, materials as well as living beings. Electric fields generally get weaker as they hit a wall or an object.
Together, electric and magnetic fields are called electromagnetic fields (EMFs).
Sources of EMF
Electromagnetic fields (EMFs) are all around us. They exist in our homes, offices, schools, and in the environment, we're surrounded by. EMFs are produced by both natural or man-made sources.
Below we'll discuss each type in detail:
Natural sources of EMF
Invisible to the human eye, natural forms of EMF exist everywhere.
Natural sources of EMF include:
Visible light — the light we can see using optical radiation (part of the electromagnetic spectrum that includes ultraviolet radiation (UV), visible light (VIS) and infrared radiation (IR)
Lightning — generated by the built-up charges in the atmosphere that also causes thunderstorms
Manmade sources of EMF
Human-generated sources of radiation are all around us and have actually blown up in recent years due to the growth of digital technology and mobile devices. They include everything from getting an X-ray to plugging a device into a power socket.
In fact, you might be surprised to know that the number of mobile phones in the world now outnumber the world's population.
Manmade sources of EMF include (but are not limited to):
Electrical Appliances — microwaves, refrigerators, washing machines, hairdryers, vacuum cleaners, blenders, etc.
Radio Communication — radio and TV stations, cordless phones, remote controls, Wi-Fi routers, air traffic control, etc.
Digital Devices — computers, laptops, mobile phones, tablets, game consoles, smartwatches, etc.
Medical imaging — X-rays, mammograms, CT scans, radiation in cancer therapy
Nuclear energy — nuclear power plants and reactors, nuclear weapons
Types of EMF
There are essentially two types of EMF exposure. Low-frequency EMF radiation, also known as non-ionizing radiation, is considered to be mild. High-frequency EMF radiation or ionizing radiation can do a lot of damage.
The way to differentiate between high and low levels of EMF are by their wavelength and their frequency levels. This is also a vital factor that determines how we as humans react to EMF. So, the higher the EMF frequency, the more energy it will produce and the more energy that is produced, the more damage it can potentially cause.
Source: Mirion Technologies
This type of low-to-mid frequency EMF radiation has lower frequencies than visible light and the frequencies are not strong enough to break through molecular bonds.
Nonetheless, these low-level EMFs can still have harmful effects on your health and due to the explosion of electrical devices we are much more exposed to this type of radiation. Examples include mobile phones, Wi-Fi, MRIs, Bluetooth, power lines, visible light, electronic gadgets, and appliances.
This type of mid-to-high frequency EMF radiation has higher frequencies than visible light and due to its ability to sever the bond between molecules, it has the potential to cause damage to cells and reach right down to the DNA level.
Sources of ionizing radiation include radon and thoron, which are natural gases that occur in rocks and soil, cosmic radiation from the sun or the solar system and natural radiation present in soil from the beginning of time. It also includes radiation from X-rays and radioactive material.
The Electromagnetic Spectrum
The Electromagnetic Spectrum signifies all the frequencies of electromagnetic energy or EM radiation. It ranges from low-frequency radiation (long wavelengths such as those of power lines) to high-frequency radiation (short wavelengths such as those of x-rays). It also includes both ionizing and non-ionizing radiation, as discussed above. The electromagnetic spectrum, made up of low to high energy frequencies, includes:
- radio waves
- infrared light
- visible light
- ultraviolet light
- gamma rays
All the frequencies of electromagnetic radiation (EMR) that you see on the spectrum are made up of light particles or "photons".
Similar to sound waves, photons also travel in waves but at the speed of light. The frequency or cycles per second (hertz), energy (volts) or wavelength (meters) of the EMR that you see on the spectrum is directly dependent on the amount of energy in the photons.
So, to put it simply, the strength of an electromagnetic field (EMF) is based on its frequency and wavelength.
The shorter the wavelength and the more the waves, the more energy is created as shown in the image below:
Let's take a closer look at each of the different frequencies that make up the electromagnetic spectrum below:
Radio Frequencies (RF)
The RF spectrum is by far one of the most important parts of the electromagnetic spectrum, especially when we talk about daily EMF exposure.
Covering frequencies from the range of 30Hz to 300GHz, radio waves are most commonly used today, primarily in the telecommunications industry.
It's important to note that radio waves are regulated by the laws of each nation and strictly controlled by the ITU (International Telecommunication Union), an international governing body. This is to limit interference and also to allocate radio frequencies to licensed providers such as television stations and cell phone carriers.
Due to its increasingly high demand, the radio spectrum has become increasingly congested over the past years, leading to an array of technological advancements such as digital two-way radio, ultra-wideband and more.
RF Radio Bands
The ITU divides radio waves into what are known as radio bands. Radio bands are frequencies that specifically fall under the RF spectrum and are divided into different ranges from ELF (extremely low frequencies) to EHF (extremely high frequencies). Each band is defined by its own frequency limit.
Popular transmission systems that you're most likely familiar with such as AM/FM radio, television broadcasting, cell phone networks, Wi-Fi, aircraft control, marine navigation, and satellite systems work within any one of these bands in the RF spectrum.
ELF (Extremely Low Frequency)
ELF is the lowest range of frequency in the RF spectrum and ranges from 3Hz to 3 kHz. It is easily susceptible to interference and can get disturbed by changes in the atmosphere. It is most commonly used by scientists to understand the Earth's natural activities such as in seismic studies (the study of earthquakes), and in marine communication.
VLF (Very Low Frequency)
Ranging from 3 kHz to 30 kHz, VLF also has fairly long wavelengths making its use in antenna systems highly complicated. This frequency range is used mainly used in communication with submarines.
LF (Low Frequency)
The LF frequency range of 30 kHz to 300 kHz is apt for long-distance communication due to its long wavelengths and the ability of the signals to get reflected by the earth's ionosphere (the ionized part of the earth's atmosphere that is able to reflect radio waves).
LF frequencies are primarily used for amateur radio as this frequency can work even when other forms of communication may fail. Other areas of application include RFID tags, submarine communication, and automatically synchronizing radio-controlled clocks.
MF (Medium Frequency)
Ranging from 300 kHz to 3 MHz, this radio frequency band has been popular since the 1800s with less complex antennas, transmitters, and receivers working on this band. The MF band is most commonly used in AM radio, aircraft and marine navigation, amateur radio and for emergency locator beacon such as avalanche beacons used by skiers.
HF (High Frequency)
The HF band ranges between 3 MHz and 30 Mhz and is also referred to as short wave. Similar to LF, this band also gets reflected by the planet's ionosphere so it is a good band for long-distance communication. The HF band is popular for certain types of radio broadcasting such as shortwave and amateur radio, RFID tags, weather broadcasts and OTH (over-the-horizon) radar which can detect targets for incredibly long distances as compared to ordinary radar.
VHF (Very High Frequency)
Originating a few decades ago, the VHF band operates from 30 MHz to 300 MHz and had become increasingly popular due to its use in analog television (before the dawn of digital TV) and FM radio broadcasting. It is also used for air traffic control, aircraft-to-aircraft communication, healthcare equipment such as MRI (magnetic resonance imaging) and military navigation.
Since different sources can define frequency ranges differently, generally frequencies that are between 300 MHz and 300 GHz are also termed as "microwaves" in the electromagnetic spectrum and include UHF (Ultra High Frequency), SHF (Super High Frequency) and EHF (Extremely High Frequency) bands as described below.
Basically, microwaves have shorter wavelengths than radio waves and move by the line of sight, meaning they travel in a "direct path from the source to the receiver." Unlike lower frequency radio waves, microwaves cannot travel as ground waves along the surface of the earth nor can they be reflected from the earth's ionosphere.
Microwaves are extensively used in technology today as you'll see below:
UHF (Ultra High Frequency)
UHF is one of the most important frequency bands as it has the most direct impact on our daily lives.
The UHF band is highly complex to implement and operates from 300 MHz to 3 GHz. This is the band used for all types of cellular transmission (GSM, LTE, and CDMA) and television broadcasting. It is also used for a lot of other applications you may be accustomed to using daily such as GPS navigation, Wi-Fi, satellite radio, cordless phone, your microwave oven, and Bluetooth.
Other applications include radio astronomy (the study of celestial bodies), remote control systems, keyless entry systems, baby monitors, and Zigbee, a communication protocol used in smart home automation and devices like the Amazon Echo Plus.
SHF (Super High Frequency)
Ranging between 3 GHz to 30 GHz the SHF band can only operate properly in a line of sight format, when there is no obstruction between the source of the signal and the receiver, as this will result in a break of transmission. Due to its smaller wavelength, design and implementation using SHF can get highly complex.
SHF is most commonly used in cable and digital television broadcasting, satellite communication, radio astronomy, radar systems, microwave ovens, cellular networks, and Wi-Fi or wireless LAN (5GHz channel).
EHF (Extremely High Frequency)
The highest frequency in the RF spectrum, EHF ranges from 30 GHz and 300 GHz. Due to its highly complex line of sight and implementation requirements, it is only used in advanced and more sophisticated communication platforms such as radio astronomy, remote sensing used in land surveying and weather analysis, and millimeter-wave scanners (part of airport security in certain airports).
This particular radio band is also the suggested frequency of use for extremely high-speed internet applications such as 5G technology due to the high-bandwidth available as seen in the image below:
So as you can see, the RF spectrum which includes both radio waves and microwaves is a key part of the electromagnetic spectrum and a lot of our digital communication platforms in the coming years may rely on radio frequencies in their ability to provide higher bandwidths.
Now we'll go on to cover other key frequencies that make up the electromagnetic spectrum.
Infrared Radiation (IR)
Infrared radiation (IR) or infrared light is a type of electromagnetic radiation with wavelengths longer than those of visible light (making it invisible to the human eye) but shorter than those of radio waves and microwaves.
Although we can't see it, we can feel infrared radiation as heat. Literally, everything on earth and the universe at large emits infrared radiation on some level, with the most common natural examples being our sun and fire.
As per NASA, infrared frequencies can range from 3 GHz to up to 400 THz.
Similar to visible light that ranges from violet to red (shortest to longest wavelength), IR also has its own wavelength range. Since it has a longer wavelength than the first color "red" on the visible light spectrum that's where it gets its name — infra-red.
IR can further be broken down to "near-infrared" and "far-infrared" waves.
Called "near-infrared" waves, the shorter wavelengths closer to the visible light spectrum don't really emit any heat - think of the red IR light on your TV remote when you flick through channels on your television.
The "far-infrared" waves, longer wavelengths which are closer to microwaves on the EM spectrum are what emit intense heat, such as natural sunlight or fire.
In fact, 50% of the sun's energy reaches the earth in the form of infrared light, the rest being ultraviolet (UV) light and visible light.
Common applications of IR radiation include toasters, flatbed scanners, heat lamps, lasers, remote controls, night vision cameras, and even standard incandescent light bulbs. In fact, according to the EPA, only 10% of the energy emitted by these bulbs is light, the other 90% is infrared radiation.
Gaining popularity for its health benefits, infrared saunas (as seen in the image above) are all the rage today due to their potential detoxification and anti-aging benefits. Unlike a standard sauna that uses heat to warm the air, an infrared sauna generates heat directly and encourages a rise in the body's temperature resulting in sweating and elimination of toxins on a cellular level.
More advanced uses of IR include military applications, weather satellites, astronomy, and art conservation.
About 40% of the sun's energy arrives on the earth in the form of visible light. Visible light carries a frequency between 430 THz to 750 THz. The visible spectrum is the part of the electromagnetic spectrum that the human eye can view, and gives us our sense of sight.
To put it simply, all EM radiation is light, and visible light is essentially the only part of this radiation that we can actually see.
Our eyes house cone-shaped cells that function as receivers, much like an antenna! They tune into the wavelength of the visible light spectrum and give us the amazing ability to view objects. Other wavelengths are simply too long or too short to be perceived biologically, and our eyes are simply not designed to see them.
Like all types of EM radiation, visible light also travels in waves. When intercepted by a prism, you can see the different wavelengths from red (longest) to orange, yellow, green, blue and violet (shortest) wavelength, as all the colors in a rainbow, as seen in the image above.
Close to 10% of the energy of the sun that enters our planet is ultraviolet (UV) radiation. It's what gives you a suntan or when exposed for longer, a sunburn. The frequency range of UV radiation oscillates between 800 THz or 10 12 hertz to about 30,000 THz.
Similar to "infra-red," less than red, which is longer in wavelength than the "red" wavelength of visible light, "ultra-violet" is shorter in wavelength than "violet," on the visible light spectrum making it "ultra" or beyond violet.
UV rays cannot be seen by the human eye, however, some insects such as hornets and bees can see them. So while certain flowers may look relatively dull to us, to certain insects they display vibrant colors and striking markings in UV light, as shown in the video below:
An important point to note is that UV radiation is ionizing, meaning it has enough energy to break through chemical bonds and cause serious damage to living tissues.
All UV radiation comes from the sun and the UV spectrum is further divided into UV-A, UV-B, and UV-C rays — the shorter the wavelength the more damaging the UV radiation.
This is the shortest wavelength and the most harmful type of UV radiation, but thankfully UV-C is entirely absorbed by the earth's atmosphere and does not reach us.
Medium in wavelength, around 95% of UV-B is absorbed and filtered by ozone in our planet's atmosphere, however, what does get through are the damaging rays that can cause sunburn, skin aging, and may even lead to cellular damage right down to the DNA level and cause diseases like skin cancer.
These are the longer wavelength UV rays and are responsible for 95% of the ultraviolet radiation that reaches the surface of the Earth. These rays can cause immediate tanning, penetrate deeper into the skin and can lead to wrinkles, premature aging, melanoma and skin cancer.
UV rays are also emitted from sun lamps, halogen lights, and tanning beds, so its best to be informed about the effects as you may be at greater risk for skin tissue damage.
UV rays are strongest between 10 am to 4 pm, but it is always advisable to wear sunscreen and covered clothing to stay protected at all times you're exposed to the sun.
The Environmental Protection Agency (EPA) has helped co-developed the UV Index with the National Weather Service that rates how strong UV rays are on a scale of 1 — 11+. The higher the number the greater the risk of damage.
If you live in the United States you can check the UV Index in your area here.
X-rays are a type of ionizing radiation and similar to UV rays can cause chemical bonds to breakdown causing damage to living tissues and cells.
X-rays or X-radiation is a type of high energy, short wavelength electromagnetic radiation. Frequencies range from 30 petahertz — 30 exahertz (3×10 16 Hz to 3×10 19 Hz). X-rays have wavelengths shorter than UV radiation but longer than gamma rays.
X-rays occur naturally in radioactive elements such as radon gas and enter the Earth through cosmic rays.
However, X-ray radiation can also be artificially generated. The most common example that you're probably most familiar with is routine medical imaging tests or "X-rays" to determine broken bones, dental issues, or other health ailments.
The most common type of X-ray medical imaging, radiography is used to determine fractures, dental and chest issues. It uses the least amount of X-ray radiation.
Fluoroscopy involves an X-ray beam being passed through the body while a continuous X-ray image is shown on the radiologist's screen and real-time pictures are taken of the body part that needs to be examined. This process uses more radiation than a routine X-ray, however, the amount of radiation is still fairly small.
Computed tomography (CT)
Best described as an intricately detailed X-ray, the patient lies down and enters a scanner. X-ray beams then pass over the patient as a 3D image of different angles is taken to generate cross-sectional snapshots of affected areas. As so many images are taken in a short period of time, CT scans use a high amount of X-ray radiation.
Since X-rays have ionizing radiation, they are classified as a potential carcinogen by the World Health Organization and the US government.
Also, high levels of radiation such as the type used in cancer radiation therapy can lead to nausea, vomiting, lightheadedness and hair loss, that is so commonly seen in cancer patients.
However, many argue that the benefits of medical imaging outweigh the effects of the radiation, as it can help to diagnose important medical issues, remove blockages and locate problems that can prove to be life-saving.
Similar to X-rays, Gamma rays occur naturally in radioactive elements which include radon gas, uranium, and plutonium, and occur in cosmic rays that enter and hit the earth's surface.
The most dangerous type of electromagnetic radiation, gamma rays have the shortest wavelength and are the type of rays emitted during nuclear fission with frequencies over 30 exahertz (3×10 19 Hz).
So what exactly is nuclear fission?
Basically, it is a nuclear reaction or a radioactive decay process in which the nucleus of an atom is bombarded by a neutron which breaks the atom into several fragments and releases more neutrons in the process, which in turn bombard other atoms.
Since this process happens in a chain reaction it releases a massive amount of energy — the kind of energy released during a nuclear bomb explosion or generated in a nuclear reactor.
Gamma rays are generated by the process of nuclear decay as seen above, while in X-rays, the rays are created outside the nucleus.
Applications of both X-rays and gamma rays include the generation of nuclear energy in power plants, airport security scanners, radiation therapy for cancer, divulging counterfeit art and nuclear weapons.
Are EMFs Harmful?
By now you know that the sun's strong rays, including the heat from your own body and the gadgets you use every day are streaming out energy waves. And, although we know that high-frequency, high energy waves like the type that caused the Chernobyl nuclear power plant disaster, are capable of doing a lot of damage — what about lower frequencies of EMF radiation in the spectrum?
To answer this, let's take a look back into history. As we entered the 20th C, power lines for electricity and interior lighting spread globally. That is when scientists recognized that similar to the sun, power lines also generated EMFs.
As the years passed, scientists discovered that just like the sun, power lines, appliances that run on electricity, including MRIs and X-rays also created their own EMFs.
As per data from the World Bank, as of 2016, almost 87% of the global population now has access to electricity and the numbers are only rising. With more electricity comes more electrical appliances, computers, mobile phones, digital devices...and more EMFs.
While many scientists don't think that the escalating number of EMF waves around us are necessarily harmful, there are many who think EMFs are a growing health concern.
Firstly, there's no argument that high-frequency EMF can be damaging — if you've ever been sunburned you know what we mean.
The main controversy today is around low-levels of EMF exposure, and how much EMF radiation is deemed acceptable at that level.
This could be a difficult question to answer due to a few reasons:
- There's not enough research to show the long-term effects of EMF exposure due to the use of Smartphones, microwave ovens, Wi-Fi, etc.
- Research done on the link between EMF and health problems is not widely publicized
- Corporate giants in the telecom and electronics industry may not want consumers to be aware of the potential harm their products could cause due to massive financial repercussions
Although there have certainly been research studies linking EMF radiation and health problems, you may not have heard much about them, due to all the reasons above.
As per a 2012 research study, the International Agency for Research on Cancer has classified ELF-EMF (1Hz to 300 Hz), which is still fairly low-frequency radio waves as being "possibly carcinogenic to humans," however more conclusive data needs to be obtained for exposure to become a concern to the public.
However, the study did go on to say that that does not negate the fact that "some human subjects may have greater sensitivity to ELF-EMF."
According to the World Health Organization (WHO), a condition termed as electromagnetic hypersensitivity (EHS), is a "real" condition where a "number of individuals have reported a variety of health problems that they relate to exposure to EMF."
Animal studies have already linked cell phone radiation to cancer, however, the ongoing debate is over whether any of these effects will be seen in humans.
When it comes to higher levels of radiation such as EHF (Extremely High Frequency), the proposed frequency band to be used for technologies such as 5G, the potential health risks may be a serious cause for concern.
This eye-opening video below discusses the potential pitfalls of 5G as being apocalyptical in nature for the planet.
Now that you know what EMF radiation is and its potential dangers, in the next few posts, we'll delve deeper into everything you need to know about EMF exposure.
- Electromagnetic fields or EMFs are both natural and artificially created energy waves that impact our daily lives
- Natural forms of EMF include the visible light from the sun, lightning and the Earth's own magnetic field
- Artificial or manmade sources of EMF include electrical appliances, radio communication, digital devices such as mobile phones, laptops, and tablets, medical imaging tests, and nuclear weapons
- EMF ranges from being low frequency to high frequency — the higher the frequency the more damaging the radiation can be
- Research has linked EMF radiation and health problems, but so far this topic has been surrounded by controversy